The GMail service went offline at 0930 GMT and, Google claims, was unavailable to all for "approximately two and a half hours".

But anecdotal evidence suggests it was out of action for many users for about four hours - one of the longest downtimes ever suffered by Google.

More than 113 million people use Google mail worldwide, according to comScore.

Back in October, some gmail users were locked out of their accounts for over a day.

We believe that cloud computing will be a very big thing over the next decade. But for all the promise of the cloud, it's worth remembering that like all new, hugely complicated technologies, the cloud will fail. Salesforce (CRM) crashed. (AMZN) struggles under heavy loads. So does Microsoft (MSFT).